ライフサイエンスコーパス: sparteine

1 ions, outperforming the benchmark ligand (-)-sparteine.

2 N',N'-tetramethylcyclohexanediamine, and (-)-sparteine.

3 n using tetramethyl- ethylenediamine and (-)-sparteine.

4 cs were observed for rate dependence on [(-)-sparteine].

5 mol, DeltaS() = -5.4 +/- 2.7 eu at high [(-)-sparteine].

6 ett rho value of -1.41 +/- 0.15 at high [(-)-sparteine].

7 e alcohol concentration at high and low [(-)-sparteine].

8 lidine have been measured in the presence of sparteine,1, N,N'-diisopropylbispidine, 2, and diaminoal

9 In the presence of catalytic CuI and sparteine, 2-formylpyrroles can be annulated with o-amin

10 bound alcohol by the deposed anion and free sparteine, (3) beta-hydride elimination through a four-c

11 ) and a 10-step, gram-scale synthesis of (-)-sparteine (31 % yield) are reported.

12 ine (4)) has been developed based on the (-)-sparteine (5)- or (+)-sparteine surrogate 11-mediated en

13 reochemistry (e.g., 73), the addition of (-)-sparteine (78) to the reaction mixture dramatically enha

14 0 equiv (-)-sparteine and with 6.0 equiv (-)-sparteine, a monomer was characterized.

15 the results with complexation studies of (-)-sparteine allows the criteria for an ideal "on/off" conf

16 Further studies of the diastereomers of (-)-sparteine, (-)-alpha-iso- and (+)-beta-isosparteine, in

17 dine (6) with two molar equiv of sec-BuL-(-)-sparteine also involves preferential transfer of the pro

18 the scarcely available and expensive diamine sparteine; also, these building blocks, together with th

19 (-)-sparteine as the base or 1 equiv of (-)-sparteine and 1 equiv of N-methyl-2-pyrrolidinone, selec

20 intermediate complexes involving i-PrLi-(-)-sparteine and 1 were located via geometry optimizations;

21 intermediate complexes involving i-PrLi-(-)-sparteine and 2 were located via geometry optimizations

22 , several ligands, structurally unrelated to sparteine and available in either enantiomeric form, wer

23 Both (-)-sparteine and O'Brien's diamine give higher optical puri

24 The chiral ligand (-)-sparteine and PdCl(2) catalyze the enantioselective oxid

25 15, and 20 (Schemes 5 and 7 ) by s-BuLi/(-)-sparteine and subsequent quench with a variety of electr

26 tructures of [(6)Li]-i-PrLi complexed to (-)-sparteine and the (+)-sparteine surrogate in Et(2)O-d(10

27 scopic monitoring of the process; use of (-)-sparteine and the (+)-sparteine surrogate to access prod

28 his preference to the bidentate character of sparteine and the lack of pi-accepting ligands.

29 e with s-BuLi in the presence of (+)- or (-)-sparteine and trapping with Me3SnCl followed by recrysta

30 )-sparteine to i-PrLi until >/=3.0 equiv (-)-sparteine and with 6.0 equiv (-)-sparteine, a monomer wa

31 prepared by asymmetric deprotonation (s-BuLi.sparteine) and stannylation, as described in the literat

32 th a variety of concentrations of amine, (-)-sparteine, and n-BuLi.

33 were accessible with a copper complex of (-)-sparteine, and the (aR)-enantiomeric series were accessi

34 l, DeltaS(++) = -24.5 +/- 2.0 eu at low [(-)-sparteine], and DeltaH(++) = 20.25 +/- 0.89 kcal/mol, De

35 kyllithium precursors in the presence of (-)-sparteine are reported.

36 ve than is the deprotonation mediated by (-)-sparteine as observed experimentally.

37 of titanium tetrachloride and 2 equiv of (-)-sparteine as the base or 1 equiv of (-)-sparteine and 1

38 protonation protocols without the use of (-)-sparteine as the chiral ligand.

39 th the opposite sense of induction using (-)-sparteine as the ligand simply by changing the reaction

40 The lithiation of 3 with sec-BuL-(-)-sparteine at -78 degrees C, which is a much slower proce

41 osed to be rate limiting, while at high [(-)-sparteine], beta-hydride elimination is proposed to be r

42 ation of the substrate scope for Pd(II)/ (-)-sparteine catalyzed aerobic oxidative kinetic resolution

43 The mechanistic details of the Pd(II)/(-)-sparteine-catalyzed aerobic oxidative kinetic resolution

44 pendencies were observed for both the Pd((-)-sparteine)Cl(2) concentration and the alcohol concentrat

45 zable continuum solvent model) for Pd(II)(-)-sparteine)(Cl)(H) and the model compound Pd(II)(bipyridi

46 The kinetics of the Pd[(-)-sparteine]Cl(2) catalyzed oxidation of decene using oxyg

47 discovered chloride dissociation from Pd[(-)-sparteine]Cl(2) prior to alcohol binding is proposed.

48 cludes (1) chloride dissociation from Pd[(-)-sparteine]Cl(2) to form cationic Pd(-)-sparteine]Cl, (2)

49 origin of enantioselectivity for the Pd[(-)-sparteine]Cl(2)-catalyzed aerobic oxidative kinetic reso

50 d[(-)-sparteine]Cl(2) to form cationic Pd(-)-sparteine]Cl, (2) alcohol binding, (3) deprotonation of

51 ovided that the intermediate lithiophosphine/sparteine complex precipitated from solution; more solub

52 ermodynamically preferred diastereomeric (-)-sparteine-complexed lithated phosphine sulfide was inves

53 Reactions of sparteine-complexed lithiated carbamates with (Z)-alkeny

54 Specifically, reactions of sparteine-complexed lithiated carbamates with trans-alke

55 ion of n-BuLi is varied independently of (-)-sparteine concentration, the reaction rate exhibits an i

56 zimidazole nitrogen, which is preferred over sparteine coordination.

57 enthoxy)phospholaneborane using a s-BuLi/(-)-sparteine derived chiral base.

58 IMes)(O2CCF3)2(OH2) (D), and Pd(O2CCF3)2/(-)-sparteine (E).

59 (-)-Sparteine failed to provide asymmetric induction in the

60 rently, enantioselective lithiation with (-)-sparteine followed by Pd(0) catalysed cross-coupling to

61 Substitution of exogenous (-)-sparteine for a more practical achiral base in the aerob

62 udy of the deprotonation of (3) by i-PrL-(-)-sparteine found that the proton that is preferentially t

63 able continuum solvent model) for Pd(II-)((-)sparteine)(H)(Cl) in the presence of base, specifically

64 g organolithium bases in the presence of (-)-sparteine has been carried out.

65 he 1:1 complex of a sec-alkyllithium and (-)-sparteine has been investigated both experimentally and

66 ion of N-Boc-pyrrolidine (1) with i-PrLi-(-)-sparteine has been studied at theoretical levels up thro

67 lcyclopropanecarboxamide (2) with i-PrLi-(-)-sparteine has been studied at theoretical levels up thro

68 n results from a concentration effect of (-)-sparteine HCl and the relative rates of reprotonation of

69 Utilizing the addition of (-)-sparteine HCl to control the [Cl(-)] and [H(+)] and the

70 dation rate in the presence of exogenous (-)-sparteine HCl.

71 dation rate was inhibited by addition of (-)-sparteine HCl.

72 Use of nBuLi and (-)-sparteine in Et(2)O at -78 degrees C gave trapped adduct

73 nation of N-Boc pyrrolidine using s-BuLi/(-)-sparteine in TBME or Et(2)O at -78 degrees C, transmetal

74 igated; it was shown that reactions with (-)-sparteine in THF proceeded with low enantioselectivity,

75 form, were found to match the utility of (-)-sparteine in this chemistry.

76 In Et(2)O, i-PrLi/(-)-sparteine is a solvent-complexed heterodimer, whereas i-

77 ally for deprotonation of 1 using t-BuLi-(-)-sparteine is attributed to a transition-state effect due

78 via this method because only one antipode of sparteine is available in nature.

79 results indicate that the complete A-ring of sparteine is essential for high levels of asymmetric ind

80 and indicated that the C(1) symmetry of (-)-sparteine is essential to the location of substitution a

81 eproduced by ONIUM calculations in which the sparteine ligand less its nitrogen atoms was treated by

82 (-)-Sparteine mediated lithiations of N-Boc-allylic and benz

83 symmetric synthesis is carried out using (-)-sparteine-mediated annelation of the axially chiral bis(

84 The (-)-sparteine-mediated asymmetric lithiation-substitution of

85 (-)-Sparteine-mediated asymmetric lithiation-substitution se

86 m by a systematic diversification of the (-)-sparteine-mediated dynamic kinetic resolution of racemic

87 In this method, (-)-sparteine-mediated enantioselective lithiation of N-Boc-

88 ined in high yield and enantioselectivity by sparteine-mediated lithiation of N-Boc-pyrrolidine and a

89 The simplest chiral portion of sparteine, N,N'-dimethyl-2-endo-methylbispidine, was pre

90 tionalized N-Boc piperazine using s-BuLi/(-)-sparteine or (+)-sparteine surrogate and provides access

91 lithium reagents, ratio of organolithium/(-)-sparteine pair versus N,N-dialkyl aryl O-carbamate start

92 At low [(-)-sparteine], Pd-alkoxide formation is proposed to be rate

93 the complexes generated were carried out on (sparteine)PdCl(2) and indicated that the C(1) symmetry o

94 responsible for the unique reactivity of (-)-sparteine-PdX(2) complexes (X = chloride, acetate) in th

95 A key, nonintuitive discovery is that (-)-sparteine plays a dual role in this oxidative kinetic re

96 henyl) allylic amines in the presence of (-)-sparteine provides asymmetric homoenolate equivalents wh

97 ed electrophiles, under the influence of (-)-sparteine, provides benzylically substituted products in

98 in the presence of the benchmark ligand (-)-sparteine, several ligands, structurally unrelated to sp

99 yield, respectively (see scheme; (-)-sp= (-)-sparteine, (+)-sps=(+)-sparteine surrogate).

100 e 1,5-diaza-cis-decalins is analogous to (-)-sparteine such that these results may permit the constru

101 An 8-step, gram-scale synthesis of the (-)-sparteine surrogate (22 % yield, with just 3 chromatogra

102 loped based on the (-)-sparteine (5)- or (+)-sparteine surrogate 11-mediated enantioselective lithiat

103 piperazine using s-BuLi/(-)-sparteine or (+)-sparteine surrogate and provides access to a range of pi

104 -PrLi complexed to (-)-sparteine and the (+)-sparteine surrogate in Et(2)O-d(10) and THF-d(8) at -80

105 onation reactions using i-PrLi or s-BuLi/(+)-sparteine surrogate in THF.

106 nt-complexed heterodimer, whereas i-PrLi/(+)-sparteine surrogate is a head-to-tail homodimer.

107 eas the corresponding reactions with the (+)-sparteine surrogate occurred with high enantioselectivit

108 In contrast, the (+)-sparteine surrogate readily complexed to i-PrLi in THF,

109 he process; use of (-)-sparteine and the (+)-sparteine surrogate to access products with opposite con

110 e scheme; (-)-sp= (-)-sparteine, (+)-sps=(+)-sparteine surrogate).

111 xed to i-PrLi in THF, and with 1.0 equiv (+)-sparteine surrogate, complete formation of a monomer was

112 successfully realized using s-BuLi and a (+)-sparteine surrogate.

113 The structural features of sparteine that led to the selectivity observed in the re

114 At high [(-)-sparteine], the selectivity is influenced by both a ther

115 At low [(-)-sparteine], the selectivity is influenced by kinetic dep

116 In THF, there was no complexation of (-)-sparteine to i-PrLi until >/=3.0 equiv (-)-sparteine and

117 lfide was lithiated with nBuLi, and then (-)-sparteine was added.

118 in the rate-limiting step by increasing [(-)-sparteine] with DeltaH(++) = 11.55 +/- 0.65 kcal/mol, De